Human granulocyte macrophage colony-stimulating factor (GM-CSF) is a glycoprotein with a molecular weight of about 23,000 dalton. The cDNA sequence and the expression of the glycoprotein in mammalian cells have already been disclosed (G. G. Wong et al., Science 228 (1985), 810-815, D. Metcalf, Science 229 (1985), 16-22).